Cessna 152 - Page 35

CESSNA
MODEL
152
SECTION3
EMERGENCY
PROCEDURES
EMERGENCY
OPERATION
IN
CLOUDS
(Vacuum System Failure)
In
the
event
of
a
vacuum
system
failure
during
flight,
the
directional
indicator
and
attitude
indicator
will
be
disabled,
and
the
pilot
will
have
to
rely
on
the
turn
coordinator
if
he
inadvertently
flies
into
clouds.
The
following
instructions
assume
that
only
the
electrically-powered
turn
coordinator
is
operative,
and
that
the
pilot
is
not
completely
proficient
in
instrument
flying.
EXECUTING A
180°
TURN
IN
CLOUDS
Upon
inadvertently
entering
the
clouds,
an
immediate
plan
should
be
made
to
turn
back
as
follows:
1.
Note
the
compass
heading.
2.
Note
the
time
of
the
minute
hand
and
observe
the
position
of
the
sweep
second
hand
on
the
clock.
3.
When
the
sweep
second
hand
indicates
the
nearest
half-minute,
initiate
a
standard
rate
left
turn,
holding
the
turn
coordinator
symbolic
airplane
wing
opposite
the
lower
left
index
mark
for
60
seconds.
Then
roll
back
to
level
flight
by
leveling
the
miniature
airplane.
4.
Check
accuracy
of
the
turn
by
observing
the
compass
heading
which
should
be
the
reciprocal
of
the
original
heading.
5.
If
necessary,
adjust
heading
primarily
with
skidding
motions
rather
than
rolling
motions
so
that
the
compass
will
read
more
accurately.
6.
Maintain
altitude
and
airspeed
by
cautious
application.of
elevator
control.
A
void
overcontrolling
by
keeping
the
hands
off
the
control
wheel
as
much
as
possible
and
steering
only
with
rudder.
EMERGENCY
DESCENT
THROUGH
CLOUDS
If
conditions
preclude
reestablishment
of
VFR
flight
by
a 180°
turn,
a
descent
through
a
cloud
deck
to
VFR
conditions
may
be
appropriate.
If
possible,
obtain
radio
clearance
for
an
emergency
descent
through
clouds.
To
guard
against
a
spiral
dive,
choose
an
easterly
or
westerly
heading
to
minimize
compass
card
swings
due
to
changing
bank
angles.
In
addition,
keep
hands
off
the
control
wheel
and
steer
a
straight
course
with
rudder
control
by
monitoring
the
turn
coordinator.
Occasionally
check
the
compass
heading
and
make
minor
corrections
to
hold
an
approximate
course.
Before
descending
into
the
clouds,
set
up
a
stabilized
let-down
condition
as
follows:
1.
Apply
full
rich
mixture.
1
July
1978
3-11